Learn Arabic (Modern Standard): عيون هؤلاء الأطفال زرق.

زرق is the plural form of the color blue. In Arabic, adjectives for colors and physical traits use the specific pattern فُعْل for their plurals. Since the singular is أزرق (masculine) and زرقاء (feminine), the plural becomes زرق.

Wait, عيون (eyes) is a non-human plural. Shouldn't it take the feminine singular adjective زرقاء?

Yes, the general rule you learned is that non-human plurals take feminine singular adjectives. However, plural body parts are a common exception! When describing the color of eyes, hair, or skin, Arabic speakers frequently use the plural فُعْل form like زرق. Using زرقاء is also grammatically correct, but زرق is very traditional and natural here.

Why doesn't عيون have ال (the) at the beginning?

Because it is the first part of an Idafa (possession phrase). The phrase عيون هؤلاء الأطفال literally means "the eyes of these children." The first word in an Idafa never takes ال, even though it translates as "the eyes" in English.

Why does هؤلاء (these) come between "eyes" and "children"?

هؤلاء means "these" and it is pointing directly to الأطفال (children). Since the whole chunk "these children" is the possessor in our Idafa structure, the pointing word هؤلاء sits exactly where "of these" would be in a literal translation: "eyes (of) these children."